hi, I have a friend with a 2000 f150 with a 4.6. Hes having problems with engine tempature. His gauge inside is reading that the car is overheating. There is no signs of actual overheating tho. When we take a temp gun to the motor it reads at about 205. we read the tempature of the coolant inside the resereve and we take the tempauture of the upper and lower radiator hoses. The car runs fine. And a few times after it said it was overheating he pulled over, turned it off for just a minutute and checked it again, and the gauge said it was back to normal (from being pegged all the way to overheating) i doubt a car can cool down that fast

We have already checked the sensor and that seems not to be the problem. What he was thinking was i guess there is some kind of resistor behind the dash that the signal gets send to before it actually displays the tempature, and he thinks that might be getting too hot, which might not give an accurate reading of correct tempature.

If anyone has any advice about what to look for, were pretty stumped and any help would be very much appreciated

 

yeah something is shorting on you. does the fan run like crazy when this happens?

If the fan isn't running then the car dosen't think it's overheating either, just your sensor. you said you checked the sensor, did you try a erplacement? the ones I'm familiar with aren't that expensive.

Does the needle instantly jump to the hotter temperature or just creep up on it until you get to the overheat?

sorry for all the questions, I'm just trying to narrow things down.

 

what was the outcome of your issue?

Thanks,
Gene

 

The fan is blet driven, it had better run all of the time.
The temp gauge is actually reading cylinder head temp, not coolant temp. Sounds like you have a bad sending unit for the gauge. Commonly called a temp. switch at most autoparts stores. The PCM reads coolant temp and cylinder head temp. The gauge just goes by cylinder head temp.
Does the truck go into overheat mode and drop ever other cylinder? If not, it could be a cluster problem.